Field
A negative active material for a rechargeable lithium battery, and a negative electrode and a rechargeable lithium battery including the same are disclosed.
Description of the Related Technology
A rechargeable lithium battery includes positive and negative electrodes including a material that can reversibly intercalate/deintercalate lithium ions as positive and negative active materials and an organic electrolyte solution or a polymer electrolyte solution charged between the positive and negative electrodes. Thus, the positive and negative electrodes intercalate and deintercalate lithium ions and produce electrical energy through oxidation and reduction reactions.
For the positive active material for a rechargeable lithium battery, lithium-transition metal oxide compounds capable of intercalating lithium such as LiCoO2, LiMn2O4, LiNi1−xCoxO2 (0<x<1), and the like has been used.
As for a negative active material for a lithium rechargeable battery, various carbon-based materials such as artificial graphite, natural graphite, and hard carbon capable of intercalating and deintercalating lithium ions have been used. Recently, the demand for a battery having higher energy densities has required a negative active material having high theoretical capacity density. Accordingly, Si, Sn, and Ge alloyed with lithium an oxide thereof and an alloy thereof have drawn attention. In particular, a Si-based negative active material has very high charge capacity and is widely applied to high-capacity batteries.
However, the volume of the silicon-based negative active material greater than or equal to about four times expands as a cycle goes, which deteriorates cycle-life and stability of a battery. Accordingly, an attempt to solve this problem has been made by using a technology of decreasing stoichiometric ratio of silicon, but the silicon-based negative active material still has a serious deterioration problem in terms of capacity, cycle-life, and stability, and the like according to the volume expansion. The embodiments set forth below addresses these problems and provides further advantages as well.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the disclosure, and therefore, it may contain information that does not form the prior art already known in this country to a person of ordinary skill in the art.